1. Technical Field:
This invention relates to devices for directing gas into a mass of molten metal around the tap hole in a metallurgical vessel so as to cause an upward swirling and bubbling rising column of molten metal acting to move slag thereon away from the tap hole so that only clean metal is tapped from the vessel.
2. Description of the Prior Art:
Devices have been heretofore used for insufflating gas into a mass of molten metal for stirring the metal and/or introducing desirable agents and/or addivites into the molten metal. Such devices have incorporated porous plugs and impervious plugs with spaced sleeves thereabout adapted to provide passageways for gas therethrough. The latter devices may be seen in U.S. Pat. Nos. 4,396,179 to LaBate, 4,483,520 to LaBate, 4,538,795 to Labate, 4,632,367 to LaBate, 4,687,184 to LaBate, et al., and 4,725,047 to LaBate.
No devices are known that are capable of or being used to surround a tap hole in a metallurgical vessel for creating an upward bubbling swirling current of molten metal capable of moving slag on the molten metal away from the tap hole area so that only clean metal is tapped from the vessel.